Help - Potterton Flamingo 50?

Heating system not working - water in rads - pump working when system switched on, but doesn't appear that the boiler fires up - pilot light ok. System was working ok last week, but just suddenly stopped heating the rads. Everything I have checked so far seems to point to the faulty boiler (not firing up).

Any ideas why that might be - or any tests I could do to find the problem ?

Another useful thing to have would be a manual for the boiler - havn't got one and can't seem to find one anywhere online - even at potterton main site (think the boiler is too old)

Any ideas where I might find one ?

Any help very much appreciated

Thanks all
Dave